The present invention relates to diffusion bonded metal laminates, and more particularly, to an apparatus and method of making long, continuous, diffusion bonded metal, laminates.
The oil and gas industries employ specialty pipes for oil and gas wells. One type of specialty pipe used down-hole, is called a xe2x80x9csand control screenxe2x80x9d. These screens prevent sand and debris from passing from the outside of the pipe to the inside of the pipe while allowing the petroleum products (oil and/or gas) to pass from the outside of the pipe to the inside of the pipe. These down-hole sand control screens typically consist of a perforated metal core, sometimes called a center-pipe, surrounded on its circumference by a permeable, porous metal layer sometimes called a porous metal media, which is further surrounded on its circumference by a perforated metal pipe sometimes called a shroud or a sheath.
These pipes, therefore, are a composite of metal materials whose center layer is porous, permeable, and is itself, a composite of porous, permeable materials.
The porous metal media that is situated between the inner core and the outer shroud is typically made of one or more of the following constructions:
multiple layers of stainless steel mesh either diffusion bonded to each other or not diffusion bonded to each other, or
a multitude of layers of stainless steel random fiber media combined with layers of stainless steel mesh either diffusion bonded to each other or not diffusion bonded to each other, or
layers of stainless steel powder combined with layers of stainless steel mesh and/or stainless steel random fiber media either diffusion bonded (or sinter bonded) to each other or not diffusion bonded (or not sinter bonded) to each other. Other constructions exist that are not described here.
The porous metal media situated between the core and the outer shroud serves to exclude the flow of sand and debris while allowing the flow of petroleum products, and therefore, acts as a filter. One frequent construction of the porous metal media is a combination of stainless steel woven wire mesh and random fiber media, diffusion bonded to each other to form a single composite. The construction of this porous, permeable composite requires the joining of layers of materials that may be dissimilar in many ways including their basic structure (woven wire mesh vs. random fiber cloth), their alloy, and their surface texture.
Today, the porous, permeable composite situated between the inner core and the outer shroud is produced from small laminate panels, whose greatest length is typically less than 5 feet long. With the current best practice, continuous laminate panels whose length is greater than about 5 feet cannot be made. This limitation is created by the physical size of the furnaces available in today""s market. As of today, the largest dimension of any continuous, diffusion bonded laminate panel made with a batch furnace, is limited to the largest internal length of that furnace. Sand control screens are typically much greater in length than these porous metal media laminate panels, and in many cases may be greater than six (6) times the maximum length of the porous metal media laminate panel. Thus, between 4 and 5 panels of porous metal media laminate need to be fastened/connected together (typically by welding) end on end to form a larger, longer porous metal media laminate panel whose length will then be sufficient to cover the entire length of the sand control screen. The longer porous metal media laminate panel resulting from this joining process is called a contiguous laminate panel, and it is discontinuous. The requirement to weld individual panels together to arrive at a long, contiguous laminate panel, poses a significant problem to the producers of sand control screens. Those difficulties include the following:
errors in the application of welding/joining the small laminate panels together can create unacceptably large holes in the porous, permeable composite which in turn, will allow the passing through of sand and debris which could damage above-ground equipment;
the application of welding changes the permeability of the porous metallic media at the weld and thus prevents, impedes or disturbs the normal flow of petroleum products at that location;
the application of welding adds cost to the sand control screen;
the application of welding causes the porous, permeable media to have different elongation, strength and thickness properties at the weld joint, and thus causes problems in the construction of the sand control screen.
Accordingly, there is a need in the art to provide a long, continuous diffusion bonded laminate with consistent mechanical and physical properties, and where existing heating furnaces can be employed.
The present invention relates to a method of producing, and an apparatus for producing, a long, continuous metal laminate that can be used in the production of a wide variety of products, such as, but not limited to, sand-control screens of long lengths. The invention allows this long laminate to be porous or non-porous, and permeable or non-permeable, depending on whether or not porosity is a requirement of the composite for the particular application.
This same method of producing, and the apparatus for producing a long, continuous, metal laminate has many other applications besides the metal laminate used to produce sand control screens. Long continuous, metal laminates produced per this invention can be used in applications such as:
the construction of polymer fiber air quench systems that require large, continuous, porous laminates as part of their construction;
the construction of long molten polymer filter elements;
the construction of long/large air diffusion panels requiring continuous mechanical properties across their length so as not to create a disturbed air flow.
The method for producing a continuous laminate begins with a rewinder drum, (sometimes called a hub or a reel), adapted for receiving a plurality of layers of strip materials that are wound around the circumference of the rewinder drum. Strips of refractory material, along with perforated metal, metal mesh, random fiber media, and/or foils are simultaneously wound around the circumference of the rewinder drum. The layers of wound material on the rewinder drum form a laminate reel that is then placed into a suitable furnace for diffusion bonding. Once cooled, the long, continuous laminate is unwound from the metal hub, the refractory material removed, and the continuous laminate can then be used in the construction of a sand control screen of desired lengths, and/or other applications where long, continuous metal laminates are preferable to non-continuous metal laminates. By forming the continuous laminate coil in this manner, it is possible to employ conventional heat treatment furnaces. Thus, the method of the invention enables one to form very long lengths of metal laminate, the length of which is greater than the length of the furnace, which would not be possible using conventional batch furnace technology. These very long lengths of metal laminate can then be used to construct very long sand control screens, and/or other products requiring long, continuous, metal laminates.
In one embodiment of the invention, the apparatus employing the method for making the continuous laminate coil employs a stainless steel hub coated with a suitable ceramic material, such as zirconia fiber material. A plurality of metal mesh strips e.g. four, a perforated metal strip, and a refractory material strip are simultaneously wound around the circumference of this stainless steel hub. The layer of refractory is placed on one side of the perforated metal strip which is in contact with the hub surface. The ensemble is then heated in a high temperature furnace. The outcome of this.process is that the four layers of mesh are bonded to each other and to the perforated metal strip to form a long metal, porous, and permeable laminate, which can be subsequently used to form a sand control screen by spiral winding the laminate.
In another embodiment of the invention, the apparatus employing the method for making the continuous laminate coil employs a stainless steel hub coated with a suitable ceramic material, such as zirconia fiber material. Three metal mesh strips, a metal foil strip, and two layers of refractory material strip are simultaneously wound around the circumference of the stainless steel hub. One layer of refractory is placed on each side of the metal foil strip. The ensemble is then heated in a high temperature furnace. The outcome of this process is that the three layers of mesh are bonded to each other and not to the metal foil strip, and, form a long mesh laminate.
Numerous other combinations of two or more strips of refractory material, perforated metal, random fiber metal media and metal mesh, which are simultaneously wound around the circumference of the rewinder drum, are feasible. The combination depends on the requirements of the laminate for the particular application.